/* * Bitops Module * * Copyright (C) 2010 Corentin Chary * * Mostly inspired by (stolen from) linux/bitmap.h and linux/bitops.h * * This work is licensed under the terms of the GNU LGPL, version 2.1 or later. * See the COPYING.LIB file in the top-level directory. */ #ifndef BITOPS_H #define BITOPS_H #include "host-utils.h" #include "atomic.h" #define BITS_PER_BYTE CHAR_BIT #define BITS_PER_LONG (sizeof (unsigned long) * BITS_PER_BYTE) #define BIT(nr) (1UL << (nr)) #define BIT_ULL(nr) (1ULL << (nr)) #define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG)) #define BIT_WORD(nr) ((nr) / BITS_PER_LONG) #define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long)) #define MAKE_64BIT_MASK(shift, length) \ (((~0ULL) >> (64 - (length))) << (shift)) /** * set_bit - Set a bit in memory * @nr: the bit to set * @addr: the address to start counting from */ static inline void set_bit(long nr, unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = addr + BIT_WORD(nr); *p |= mask; } /** * set_bit_atomic - Set a bit in memory atomically * @nr: the bit to set * @addr: the address to start counting from */ static inline void set_bit_atomic(long nr, unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = addr + BIT_WORD(nr); qatomic_or(p, mask); } /** * clear_bit - Clears a bit in memory * @nr: Bit to clear * @addr: Address to start counting from */ static inline void clear_bit(long nr, unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = addr + BIT_WORD(nr); *p &= ~mask; } /** * clear_bit_atomic - Clears a bit in memory atomically * @nr: Bit to clear * @addr: Address to start counting from */ static inline void clear_bit_atomic(long nr, unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = addr + BIT_WORD(nr); return qatomic_and(p, ~mask); } /** * change_bit - Toggle a bit in memory * @nr: Bit to change * @addr: Address to start counting from */ static inline void change_bit(long nr, unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = addr + BIT_WORD(nr); *p ^= mask; } /** * test_and_set_bit - Set a bit and return its old value * @nr: Bit to set * @addr: Address to count from */ static inline int test_and_set_bit(long nr, unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = addr + BIT_WORD(nr); unsigned long old = *p; *p = old | mask; return (old & mask) != 0; } /** * test_and_clear_bit - Clear a bit and return its old value * @nr: Bit to clear * @addr: Address to count from */ static inline int test_and_clear_bit(long nr, unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = addr + BIT_WORD(nr); unsigned long old = *p; *p = old & ~mask; return (old & mask) != 0; } /** * test_and_change_bit - Change a bit and return its old value * @nr: Bit to change * @addr: Address to count from */ static inline int test_and_change_bit(long nr, unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = addr + BIT_WORD(nr); unsigned long old = *p; *p = old ^ mask; return (old & mask) != 0; } /** * test_bit - Determine whether a bit is set * @nr: bit number to test * @addr: Address to start counting from */ static inline int test_bit(long nr, const unsigned long *addr) { return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1))); } /** * find_last_bit - find the last set bit in a memory region * @addr: The address to start the search at * @size: The maximum size to search * * Returns the bit number of the last set bit, * or @size if there is no set bit in the bitmap. */ unsigned long find_last_bit(const unsigned long *addr, unsigned long size); /** * find_next_bit - find the next set bit in a memory region * @addr: The address to base the search on * @offset: The bitnumber to start searching at * @size: The bitmap size in bits * * Returns the bit number of the next set bit, * or @size if there are no further set bits in the bitmap. */ unsigned long find_next_bit(const unsigned long *addr, unsigned long size, unsigned long offset); /** * find_next_zero_bit - find the next cleared bit in a memory region * @addr: The address to base the search on * @offset: The bitnumber to start searching at * @size: The bitmap size in bits * * Returns the bit number of the next cleared bit, * or @size if there are no further clear bits in the bitmap. */ unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size, unsigned long offset); /** * find_first_bit - find the first set bit in a memory region * @addr: The address to start the search at * @size: The maximum size to search * * Returns the bit number of the first set bit, * or @size if there is no set bit in the bitmap. */ static inline unsigned long find_first_bit(const unsigned long *addr, unsigned long size) { unsigned long result, tmp; for (result = 0; result < size; result += BITS_PER_LONG) { tmp = *addr++; if (tmp) { result += ctzl(tmp); return result < size ? result : size; } } /* Not found */ return size; } /** * find_first_zero_bit - find the first cleared bit in a memory region * @addr: The address to start the search at * @size: The maximum size to search * * Returns the bit number of the first cleared bit, * or @size if there is no clear bit in the bitmap. */ static inline unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size) { return find_next_zero_bit(addr, size, 0); } /** * rol8 - rotate an 8-bit value left * @word: value to rotate * @shift: bits to roll */ static inline uint8_t rol8(uint8_t word, unsigned int shift) { return (word << (shift & 7)) | (word >> (-shift & 7)); } /** * ror8 - rotate an 8-bit value right * @word: value to rotate * @shift: bits to roll */ static inline uint8_t ror8(uint8_t word, unsigned int shift) { return (word >> (shift & 7)) | (word << (-shift & 7)); } /** * rol16 - rotate a 16-bit value left * @word: value to rotate * @shift: bits to roll */ static inline uint16_t rol16(uint16_t word, unsigned int shift) { return (word << (shift & 15)) | (word >> (-shift & 15)); } /** * ror16 - rotate a 16-bit value right * @word: value to rotate * @shift: bits to roll */ static inline uint16_t ror16(uint16_t word, unsigned int shift) { return (word >> (shift & 15)) | (word << (-shift & 15)); } /** * rol32 - rotate a 32-bit value left * @word: value to rotate * @shift: bits to roll */ static inline uint32_t rol32(uint32_t word, unsigned int shift) { return (word << (shift & 31)) | (word >> (-shift & 31)); } /** * ror32 - rotate a 32-bit value right * @word: value to rotate * @shift: bits to roll */ static inline uint32_t ror32(uint32_t word, unsigned int shift) { return (word >> (shift & 31)) | (word << (-shift & 31)); } /** * rol64 - rotate a 64-bit value left * @word: value to rotate * @shift: bits to roll */ static inline uint64_t rol64(uint64_t word, unsigned int shift) { return (word << (shift & 63)) | (word >> (-shift & 63)); } /** * ror64 - rotate a 64-bit value right * @word: value to rotate * @shift: bits to roll */ static inline uint64_t ror64(uint64_t word, unsigned int shift) { return (word >> (shift & 63)) | (word << (-shift & 63)); } /** * hswap32 - swap 16-bit halfwords within a 32-bit value * @h: value to swap */ static inline uint32_t hswap32(uint32_t h) { return rol32(h, 16); } /** * hswap64 - swap 16-bit halfwords within a 64-bit value * @h: value to swap */ static inline uint64_t hswap64(uint64_t h) { uint64_t m = 0x0000ffff0000ffffull; h = rol64(h, 32); return ((h & m) << 16) | ((h >> 16) & m); } /** * wswap64 - swap 32-bit words within a 64-bit value * @h: value to swap */ static inline uint64_t wswap64(uint64_t h) { return rol64(h, 32); } /** * extract32: * @value: the value to extract the bit field from * @start: the lowest bit in the bit field (numbered from 0) * @length: the length of the bit field * * Extract from the 32 bit input @value the bit field specified by the * @start and @length parameters, and return it. The bit field must * lie entirely within the 32 bit word. It is valid to request that * all 32 bits are returned (ie @length 32 and @start 0). * * Returns: the value of the bit field extracted from the input value. */ static inline uint32_t extract32(uint32_t value, int start, int length) { assert(start >= 0 && length > 0 && length <= 32 - start); return (value >> start) & (~0U >> (32 - length)); } /** * extract8: * @value: the value to extract the bit field from * @start: the lowest bit in the bit field (numbered from 0) * @length: the length of the bit field * * Extract from the 8 bit input @value the bit field specified by the * @start and @length parameters, and return it. The bit field must * lie entirely within the 8 bit word. It is valid to request that * all 8 bits are returned (ie @length 8 and @start 0). * * Returns: the value of the bit field extracted from the input value. */ static inline uint8_t extract8(uint8_t value, int start, int length) { assert(start >= 0 && length > 0 && length <= 8 - start); return extract32(value, start, length); } /** * extract16: * @value: the value to extract the bit field from * @start: the lowest bit in the bit field (numbered from 0) * @length: the length of the bit field * * Extract from the 16 bit input @value the bit field specified by the * @start and @length parameters, and return it. The bit field must * lie entirely within the 16 bit word. It is valid to request that * all 16 bits are returned (ie @length 16 and @start 0). * * Returns: the value of the bit field extracted from the input value. */ static inline uint16_t extract16(uint16_t value, int start, int length) { assert(start >= 0 && length > 0 && length <= 16 - start); return extract32(value, start, length); } /** * extract64: * @value: the value to extract the bit field from * @start: the lowest bit in the bit field (numbered from 0) * @length: the length of the bit field * * Extract from the 64 bit input @value the bit field specified by the * @start and @length parameters, and return it. The bit field must * lie entirely within the 64 bit word. It is valid to request that * all 64 bits are returned (ie @length 64 and @start 0). * * Returns: the value of the bit field extracted from the input value. */ static inline uint64_t extract64(uint64_t value, int start, int length) { assert(start >= 0 && length > 0 && length <= 64 - start); return (value >> start) & (~0ULL >> (64 - length)); } /** * sextract32: * @value: the value to extract the bit field from * @start: the lowest bit in the bit field (numbered from 0) * @length: the length of the bit field * * Extract from the 32 bit input @value the bit field specified by the * @start and @length parameters, and return it, sign extended to * an int32_t (ie with the most significant bit of the field propagated * to all the upper bits of the return value). The bit field must lie * entirely within the 32 bit word. It is valid to request that * all 32 bits are returned (ie @length 32 and @start 0). * * Returns: the sign extended value of the bit field extracted from the * input value. */ static inline int32_t sextract32(uint32_t value, int start, int length) { assert(start >= 0 && length > 0 && length <= 32 - start); /* Note that this implementation relies on right shift of signed * integers being an arithmetic shift. */ return ((int32_t)(value << (32 - length - start))) >> (32 - length); } /** * sextract64: * @value: the value to extract the bit field from * @start: the lowest bit in the bit field (numbered from 0) * @length: the length of the bit field * * Extract from the 64 bit input @value the bit field specified by the * @start and @length parameters, and return it, sign extended to * an int64_t (ie with the most significant bit of the field propagated * to all the upper bits of the return value). The bit field must lie * entirely within the 64 bit word. It is valid to request that * all 64 bits are returned (ie @length 64 and @start 0). * * Returns: the sign extended value of the bit field extracted from the * input value. */ static inline int64_t sextract64(uint64_t value, int start, int length) { assert(start >= 0 && length > 0 && length <= 64 - start); /* Note that this implementation relies on right shift of signed * integers being an arithmetic shift. */ return ((int64_t)(value << (64 - length - start))) >> (64 - length); } /** * deposit32: * @value: initial value to insert bit field into * @start: the lowest bit in the bit field (numbered from 0) * @length: the length of the bit field * @fieldval: the value to insert into the bit field * * Deposit @fieldval into the 32 bit @value at the bit field specified * by the @start and @length parameters, and return the modified * @value. Bits of @value outside the bit field are not modified. * Bits of @fieldval above the least significant @length bits are * ignored. The bit field must lie entirely within the 32 bit word. * It is valid to request that all 32 bits are modified (ie @length * 32 and @start 0). * * Returns: the modified @value. */ static inline uint32_t deposit32(uint32_t value, int start, int length, uint32_t fieldval) { uint32_t mask; assert(start >= 0 && length > 0 && length <= 32 - start); mask = (~0U >> (32 - length)) << start; return (value & ~mask) | ((fieldval << start) & mask); } /** * deposit64: * @value: initial value to insert bit field into * @start: the lowest bit in the bit field (numbered from 0) * @length: the length of the bit field * @fieldval: the value to insert into the bit field * * Deposit @fieldval into the 64 bit @value at the bit field specified * by the @start and @length parameters, and return the modified * @value. Bits of @value outside the bit field are not modified. * Bits of @fieldval above the least significant @length bits are * ignored. The bit field must lie entirely within the 64 bit word. * It is valid to request that all 64 bits are modified (ie @length * 64 and @start 0). * * Returns: the modified @value. */ static inline uint64_t deposit64(uint64_t value, int start, int length, uint64_t fieldval) { uint64_t mask; assert(start >= 0 && length > 0 && length <= 64 - start); mask = (~0ULL >> (64 - length)) << start; return (value & ~mask) | ((fieldval << start) & mask); } /** * half_shuffle32: * @x: 32-bit value (of which only the bottom 16 bits are of interest) * * Given an input value:: * * xxxx xxxx xxxx xxxx ABCD EFGH IJKL MNOP * * return the value where the bottom 16 bits are spread out into * the odd bits in the word, and the even bits are zeroed:: * * 0A0B 0C0D 0E0F 0G0H 0I0J 0K0L 0M0N 0O0P * * Any bits set in the top half of the input are ignored. * * Returns: the shuffled bits. */ static inline uint32_t half_shuffle32(uint32_t x) { /* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits". * It ignores any bits set in the top half of the input. */ x = ((x & 0xFF00) << 8) | (x & 0x00FF); x = ((x << 4) | x) & 0x0F0F0F0F; x = ((x << 2) | x) & 0x33333333; x = ((x << 1) | x) & 0x55555555; return x; } /** * half_shuffle64: * @x: 64-bit value (of which only the bottom 32 bits are of interest) * * Given an input value:: * * xxxx xxxx xxxx .... xxxx xxxx ABCD EFGH IJKL MNOP QRST UVWX YZab cdef * * return the value where the bottom 32 bits are spread out into * the odd bits in the word, and the even bits are zeroed:: * * 0A0B 0C0D 0E0F 0G0H 0I0J 0K0L 0M0N .... 0U0V 0W0X 0Y0Z 0a0b 0c0d 0e0f * * Any bits set in the top half of the input are ignored. * * Returns: the shuffled bits. */ static inline uint64_t half_shuffle64(uint64_t x) { /* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits". * It ignores any bits set in the top half of the input. */ x = ((x & 0xFFFF0000ULL) << 16) | (x & 0xFFFF); x = ((x << 8) | x) & 0x00FF00FF00FF00FFULL; x = ((x << 4) | x) & 0x0F0F0F0F0F0F0F0FULL; x = ((x << 2) | x) & 0x3333333333333333ULL; x = ((x << 1) | x) & 0x5555555555555555ULL; return x; } /** * half_unshuffle32: * @x: 32-bit value (of which only the odd bits are of interest) * * Given an input value:: * * xAxB xCxD xExF xGxH xIxJ xKxL xMxN xOxP * * return the value where all the odd bits are compressed down * into the low half of the word, and the high half is zeroed:: * * 0000 0000 0000 0000 ABCD EFGH IJKL MNOP * * Any even bits set in the input are ignored. * * Returns: the unshuffled bits. */ static inline uint32_t half_unshuffle32(uint32_t x) { /* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits". * where it is called an inverse half shuffle. */ x &= 0x55555555; x = ((x >> 1) | x) & 0x33333333; x = ((x >> 2) | x) & 0x0F0F0F0F; x = ((x >> 4) | x) & 0x00FF00FF; x = ((x >> 8) | x) & 0x0000FFFF; return x; } /** * half_unshuffle64: * @x: 64-bit value (of which only the odd bits are of interest) * * Given an input value:: * * xAxB xCxD xExF xGxH xIxJ xKxL xMxN .... xUxV xWxX xYxZ xaxb xcxd xexf * * return the value where all the odd bits are compressed down * into the low half of the word, and the high half is zeroed:: * * 0000 0000 0000 .... 0000 0000 ABCD EFGH IJKL MNOP QRST UVWX YZab cdef * * Any even bits set in the input are ignored. * * Returns: the unshuffled bits. */ static inline uint64_t half_unshuffle64(uint64_t x) { /* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits". * where it is called an inverse half shuffle. */ x &= 0x5555555555555555ULL; x = ((x >> 1) | x) & 0x3333333333333333ULL; x = ((x >> 2) | x) & 0x0F0F0F0F0F0F0F0FULL; x = ((x >> 4) | x) & 0x00FF00FF00FF00FFULL; x = ((x >> 8) | x) & 0x0000FFFF0000FFFFULL; x = ((x >> 16) | x) & 0x00000000FFFFFFFFULL; return x; } #endif